The invention relates to an apparatus for the treatment of tumors, the apparatus comprising at least one generator having a power source, and at least two needle electrodes by means of which current can be conducted into, and out of, the tumor.
Such an apparatus is for instance known from the document “Percutaneous Bio-electrotherapy of Cancerous Tumors”, Dr. Med. Rudolf Pekar, Publishing House Wilhelm Maudrich, Vienna-Munich-Berne, 1997. The apparatus disclosed therein comprises two needle-shaped electrodes, one for conducting current into the tumor and one for conducting current out of the tumor. By means of the apparatus known, direct current is conducted through a tumor. This is done by inserting the two needle-shaped electrodes into the tumor, and then applying a DC voltage to the electrodes, so that a direct current flows through the tumor. Such a current is intended to destroy cancerous cells in the tumor.
It has been found that the method is more efficient the more current is conducted through the tumor. Therefore a current is selected which is as high as possible. Since, however, it has also been found that the tissue around the insertion location of the needle-shaped electrode is undesirably damaged by a current of approximately 80 milliampere and more, the current cannot be increased arbitrarily with an apparatus having needle-shaped electrodes.
The apparatus known from the document mentioned comprises two systems with separate outputs. It would thus be conceivable to use both systems in a parallel treatment of one and the same tumor. The current conducted into the tumor might then actually be doubled, with the current conducted into the tumor by each of the electrodes being limited to a maximum value. Since, however, the current travels through the tumor in an uncontrolled manner, it is not guaranteed that the current will, in correspondence with its introduction, again be conducted out of the tumor via the respective pertinent electrode. There is rather the risk that, due to the inhomogenous electric conductivity of the tumor, the current will pass through the tumor in such a way that it predominantly exits via one electrode, and that merely a residual current is conducted out of the tumor via the other electrode. This would destroy the tissue around the needle-shaped electrode via which the major part of the current exits from the tumor. The document therefore does not indicate, either that the two systems may be used in parallel for the treatment of one tumor, but rather it is indicated that the two systems are provided for the treatment of two patients that is of two different tumors at a time.
It the principal an object of the invention to provide an apparatus for the treatment of tumors such that it is suited for the unproblematic treatment of tumors with relatively high currents.